Doing ribs today thought about slicing red potatoes 1/8 in. thick little garlic,onion,and oil and S&P putting in tinfoil bag and putting them on the smoker with the ribs. How long do you think they have to be on for ??????
I do them on the weber kettle all the time, and mostly foiled takes around an hour (cut in quarters and I leave the top open for a while, cooked about 350).
Only question is why would you want to do potatoes with a "little" onion and garlic?
I've never had much luck on the WSM because of the temps. I also make potatoes this way on the kettle. Sometimes in the foil, and sometimes not. I usually use butter instead of oil. I also like to add fresh peppers when they're in season. For sliced potatoes, I cook them about 45 minutes with the grill at about 350.
I've never had a problem cooking potatoes on the WSM. High temps or not. I usually throw them on when I make whole chickens. Everything cooks at roughly 250-280F. And yes, I foil the potatoes!